In the prior art chair disclosed in Heyl, Jr. et al U.S. Pat. No. 3,138,402, a parallelogram lift linkage is actuated by rotating a bell crank against the lift links to create a movement about the pivot connection between the links and the base which rests on the floor to rotate the links to the raised position. This arrangement requires that the linkage hold the weight of the chair and occupant in cantilever from the rear of the links in the raised position. As a result of greater stress on the pivots of the linkage, this arrangement results in instability (i.e. a feeling of looseness) of the linkage on the part of the occupant at the elevated or raised position. Moreover, the seat of the chair of this patent is arranged into a forward portion which does not rise when the chair is elevated, and a rear portion which does rise and is tilted forwardly when the chair is elevated. If the seat of heyl, Jr. et al were not divided into two sections, the occupant would be forced to move his or her feet forwardly when getting out of the chair.
Another lift assist chair disclosed in the prior art Gaffney U.S. Pat. No. 4,007,960. However, the lift linkage is arranged so that it rotated about the rear of the chair base. This results in moving the occupant rearwardly when raising the chair form the normal rest position to the elevated exit position and requires the occupant to shift his or her feet relatively to the rest position in order to alight from the chair. Shifting of the feet of the occupant is considered disadvantageous, especially for severely handicapped persons or those suffering form advanced stages of arthritis.